{"record":{"author":{"account_ref":null,"orcid":null},"builds_on":[],"content_schema":"pubphys.content.revision/1","content_sha256":"cbe94b08dc9d8db0e9675aec4b1bd84ccfdba175d6a379eb93cdc84a11a565be","created":"2026-10-15T23:43:22Z","files":[],"origin":{"assisted_by":["ai:gpt-5.5"],"kind":"seed"},"parents":["2b14938296c8ad1e49b251b2043ee7e420f8aee7ccd506042537a27815ad01d0","ce59fb6cd812fc05906d0c60a71c75ea22bc686bcf38e7c3ef7010834d98ee7b"],"salt":"7eddc6c61852724501d058ad349c050ab65a98e665d6de20daaba0213c34abab","schema":"pubphys.record/2","site":"pubphys.com","target":null,"type":"revision"},"content":{"answer_type":"yes-no","assisted_by":["ai:gpt-5.5"],"external_id":"hep.strong-cp.qcd-axion-existence","kind":"well-posed","literature_status":"open","n":"2","parents":[],"plain":"The axion would be a very light, very weakly interacting particle that removes the strong CP puzzle. Detectors search for it turning into a photon inside strong magnets.","posed_since":"1978","precise":"Determine whether a pseudoscalar a with $m_a \\sim 5.7\\ \\mathrm{micro-eV}\\ (10^{12}\\ \\mathrm{GeV}/f_a)$ and photon coupling $g_{agamma}$ inside the QCD axion band (KSVZ to DFSZ and beyond) exists, for $f_a\\ \\text{between}\\ \\sim 10^{8}\\ \\text{and}\\ \\sim 10^{17}\\ \\mathrm{GeV}$. An answer is a detection with $m_a$ and $g_{agamma}$ consistent with the QCD mass-decay constant relation, or exclusion of the band over the full range.","problem_ref":"2b14938296c8ad1e49b251b2043ee7e420f8aee7ccd506042537a27815ad01d0","references":"","settled_by":"Haloscope, helioscope (IAXO) and nuclear-coupling (CASPEr-type) searches covering the QCD axion band across micro-eV to meV masses.","status_note":"Haloscopes reach DFSZ sensitivity only in narrow windows of a few micro-eV as of 2025.","title":"Does the QCD axion exist?","topic_ref":null},"attested":{"attestation":{"batch":null,"client_id":null,"id_token_sha256":null,"kind":"platform"},"record_hash":"da79a19b082e330cd4029507e9fa93d4b18ef5ca9173ec54ce2ef153cd9f8c46","schema":"pubphys.attested/1"},"envelope":{"attested_hash":"485d0b5b5ca77680052da4e18bdd4893303b8c4e12dc1a44291f5038a17143ed","platform_signature":{"key_id":"c6afc19b31429869751f06879c75cd64ea92654423d15b44be775bf1310a60da","sig":"OlHvW6ffbaHxgKyVn9c1Sbkc-Mu06dfKE1vQhjNSsHQmIpuAYC2P32Im0sV9D1ohwwG8WTpe_4E0YCJPjbyqCA"},"schema":"pubphys.envelope/1"},"record_hash":"da79a19b082e330cd4029507e9fa93d4b18ef5ca9173ec54ce2ef153cd9f8c46","leaf_index":3386}